sickness/disease

[Jasper]

I,ve had my 25 Gal up and running about 2 wks w/2 Zebra Danios & 1 long tail ( beginning cycling w/fish. 2 days ago I added 2 plants & 2Zebra Danios along w/ 1 more long tailed Danio. One of the new Zebras died today after swimming quite lazily for a day. The largest and fattest Zebra has developed a bump just forward of the dorsal fin. As of 2 days ago all levels were good (ammonia was a little high...doing my first 25% water change today) Does my tank have the black plague?

 

[TESS]

Hello, i am new to tropical fish also and i am doing a cycle with 8 platies.
I am doing a 10% water change everyday (dont forget to add aqua safe to new water and test tempreture) and doing water test every day. I also keep the top of the tank open for 1 hour a day to air it. The ammonia in my tank is 0 and the nitrite is 0.10-0.25 the ph is 7.5 and nitrate is 40, the results are the same each day.Ive had my fish for 7 days now, they are all fine and happy so fingers crossed im doing it wright .
I hope your fish will be ok.
I will let an expert explain more though

 

[WILDER]

If ammonia gets to high do a water change, I would add some salt to the tank if you have no scaless fish, as it will help them with the cycle, you might need to use anti internal bacteria med if one of the fish has a bump.